1. The Field of the Invention
The present invention relates to pressure vessels for carrying pressurized fluids. More specifically, the present invention relates to tanks designed to support an external, compressive load as well as the pressure of the fluid, for use in applications in which lightweight storage and structural members are desirable.
2. The Relevant Technology
Pressure vessels, or storage tanks, are commonly used to store fluids under pressure. Many types of propulsion vehicles require some type of fluid storage. For example, many types of launch vehicles, spacecraft, missiles, satellites, and rocket-propelled torpedoes all store a fluid propellant. Liquid fuel rocket motors typically require tanks of pressurized, combustible fluids that can be combusted and ejected from a nozzle to propel the rocket. Many forms of electric propulsion also require a pressurized fluid propellant. The term “fluid” includes both gases and liquids; many rockets store fuels in a substantially liquid form, with a component of combustible vapor. Additionally, rockets have a number of other structural features necessary for the rocket's operation. For example, rockets may have additional tanks, nozzles to direct exhaust gases, and thrust structures designed to convey force from the nozzle to the main body of the rocket. Typically, the inside of a rocket is a mass of tubes, tanks, wiring, and fixtures.
The cost and performance requirements that rockets typically operate under frequently dictate the use of lightweight, compact components. As a result, it is desirable to minimize mass and eliminate as much unnecessary structure as possible. Many vehicle applications are also volume sensitive and require that wasted space within the vehicle be minimized wherever possible. Tanks known in the art, however, are not well-suited to compact assembly, in part because they are often shaped with symmetrical, convex walls. Consequently, space between independent tanks and requisite inter-tank structure is typical. Furthermore, tanks known in the art create an enormous blockage through which it is difficult to route wiring, plumbing, conduits, and structural features necessary for operation of the rocket. The complexity of the rocket design is compounded because every other component of the rocket must be designed around the tank.
Furthermore, rockets often contain multiple tanks to hold different fluids, such as an oxidizer and a fuel. For example, oxygen may be stored in one tank, and a suitable liquid fuel in the other, so that the two may be combined to combust even in a vacuum. The use of multiple tanks adds additional complexity, volume, and weight to the rocket. A liquid-fueled rocket must typically carry two tanks, even though the fluids contained in the tanks are stored at similar pressures and will often be routed to the same location.
Consequently, there is a need, unfulfilled by the prior art, for part count reduction and for space and weight conserving tankage that can be effectively positioned within the body of a rocket or a similar propulsion vehicle, without hindering the placement of necessary equipment. There is a further need for space-saving configurations and structures that can be effectively used with tankage for the vehicle. The tankage and structures should be easily manufactured at low expense, and easy to assemble. Furthermore, the tankage and structures should be sturdy enough to tolerate the stresses created by high acceleration and vibration.
Similarly, there is a need for novel methods of manufacture, through which improved tankage and structures can be created, assembled, and installed in a propulsion vehicle. Such methods should be rapid, inexpensive, and preferably utilize available tooling with little modification.
The current invention discloses such an apparatus and method.